Activation of a mineral species

Abstract

A method of activating a mineral species wherein the mineral species is activated by fine or ultra fine milling prior to processing by methods of oxidative hydrometallurgy. The milled mineral species may be subjected to oxidative leaching under relatively mild conditions of pressure and temperature due to the milling producing minerals which are activated, and which thus react far more readily with oxidants such as oxygen. Furthermore, the oxidative leaching is able to be conducted under conditions requiring less than stoichiometric levels of oxidant, again due to the activated nature of the minerals.

The claims defining the invention are as follows: 
     
       1. A method of preparing a mineral species for oxidative hydrometallurgy comprising the step of milling the species to P80 of about 30 microns or less. 
     
     
       2. A method according to claim 1 wherein the mineral species is a sulphide mineral, an arsenide mineral, a telluride mineral, or a mixed mineral comprising one or more of the group consisting of sulphides, arsenides and tellurides. 
     
     
       3. A method according to claim 1 wherein the milling is conducted in a vertical stirred mill. 
     
     
       4. A method according to claim 1 wherein the mineral species is a sulphide mineral and the oxidative hydrometallurgy is an oxidative leach. 
     
     
       5. A method according to claim 4 wherein the oxidative leach is conducted at relatively mild temperature and pressure and with low levels of oxidant. 
     
     
       6. A method according to claim 5 wherein the oxidative leach is conducted at temperatures below about 120° C., oxygen pressures below about 1000 kPa and with substoichiometric levels of oxygen as oxidant. 
     
     
       7. A method according to claim 1 wherein the method of oxidative hydrometallurgy is an oxidative leach conducted at relatively mild temperature and pressure and with low levels of oxidant. 
     
     
       8. A method according to claim 1 wherein the milling reduces the size of the mineral species to P80 of 15 micron or less. 
     
     
       9. A method according to claim 1 wherein the milling and subsequent processing are repeated in multiple stages. 
     
     
       10. A method of processing a mineral species, said method comprising the steps of milling the mineral species to P80 of about 30 microns or less, and oxidative leaching of the milled mineral species under relatively mild conditions of pressure and temperature and in the presence of substoichiometric levels of oxygen. 
     
     
       11. A method according to claim 11 wherein the milling is conducted in a vertical stirred mill. 
     
     
       12. A method according to claim 11 wherein the mineral species is a sulphide mineral, an arsenide mineral, a telluride mineral, or a mixed mineral comprising one or more of the group consisting of sulphides, arsenides and tellurides. 
     
     
       13. A method according to claim 11 wherein the oxidative leach is conducted at temperatures below about 120° C. and oxygen pressures below about 1000 kPa. 
     
     
       14. A method according to claim 11 wherein the milling reduces the size of the mineral species to P80 of 15 micron or less. 
     
     
       15. A method according to claim 11 wherein the steps of milling and oxidative leaching are repeated in multiple stages. 
     
     
       16. A method of processing a sulphide mineral, said method comprising the steps of fine milling the sulphide mineral in a vertical stirred mill to P80 of 15 micron or less and leaching the milled sulphide mineral with substoichiometric levels of oxygen at a temperature below about 120° C. and an oxygen pressure below about 1000 kPa.